Evaluation of lactic acid bacteria autolysate for the supplementation of lactic acid bacteria fermentation

At the end of culture in a carbon-limited medium, i.e. the best conditions for subsequent autolysis, lactic acid bacteria were harvested and autolysed at 50 °C for 24 h. The resulting supernatant was then successfully tested as a substitute for industrial yeast extract for the supplementation of whey permeate and its conversion into lactic acid: for almost equivalent total nitrogen amounts of both supplements, the same growth and production rates were recorded.     

Comparison of pattern recognition techniques for the identification of lactic acid bacteria

AIMS: The goal of this study was to evaluate three pattern recognition methods for use in the identification of lactic acid bacteria. METHODS AND RESULTS: Lactic acid bacteria (21 unknown isolates and 30 well-characterized strains), including the Lactobacillus, Lactococcus, Streptococcus, Pediococcus and Oenococcus genera, were tested for 49 phenotypic responses (acid production on carbon sources). The results were scored in several ways. Three procedures, k-nearest neighbour analysis (KNN), k-means clustering and fuzzy c-means clustering (FCM), were applied to the data. CONCLUSION: k-Nearest neighbour analysis performed better with five-point-scaled than with binary data, indicating that intermediate values are helpful to classification. k-Means clustering performed slightly better than KNN and was best with fuzzified data. The best overall results were obtained with FCM. Genus level classification was best with FCM using an exponent of 1.25. SIGNIFICANCE AND IMPACT OF THE STUDY: The three pattern recognition methods offer some advantages over other approaches to organism classification.     

金银花不同提取方法的绿原酸比较研究

本文采用了水提法、水提醇沉法、酶解法、醇提法对金银花进行提取,并用紫外分光光度法来测定提取物中绿原酸的含量,依此来比较各种方法的优劣。由实验结果可得：以绿原酸作为指标来考察各种方法的优劣,尤以醇提法较好,绿原酸的含量可达到15.28%;以提取物的得率为指标来考察,以酶解法为最好,提取物的得率可达到37.91%。     

Improved production of propionic acid using genome shuffling

Traditionally derived from fossil fuels, biological production of propionic acid has recently gained interest. Propionibacterium species produce propionic acid as their main fermentation product. Production of other organic acids reduces propionic acid yield and productivity, pointing to by‐products gene‐knockout strategies as a logical solution to increase yield. However, removing by‐product formation has seen limited success due to our inability to genetically engineer the best producing strains (i.e. Propionibacterium acidipropionici). To overcome this limitation, random mutagenesis continues to be the best path towards improving strains for biological propionic acid production. Recent advances in next generation sequencing opened new avenues to understand improved strains. In this work, we use genome shuffling on two wild type strains to generate a better propionic acid producing strain. Using next generation sequencing, we mapped the genomic changes leading to the improved phenotype. The best strain produced 25% more propionic acid than the wild type strain. Sequencing of the strains showed that genomic changes were restricted to single point mutations and gene duplications in well‐conserved regions in the genomes. Such results confirm the involvement of gene conversion in genome shuffling as opposed to long genomic insertions.     

Determining the conditions for stimulation of levorin biosynthesis in the presence of succinic acid

Conditions promoting the stimulating effect of succinic acid on biosynthesis of levorin were determined. The optimal concentration of succinate was shown to be equal to 0.05-0.3 per cent and the best time for the addition was before inoculation. The most pronounced stimulating effect was observed when the initial pH value of the fermentation medium was equal to 7.0. The important role of ammonium nitrogen in manifestation of the succinic acid stimulating effect on biosynthesis of levorin was suggested.     

Biosynthesis of folic acid

Summary Biosynthesis of folic acid activity by Bacillus subtilis cell suspensions was studied with respect to substrates utilized as precursors. Among purine bases, adenine was utilized the best and not guanine although guanosine or guanylic acid were utilized efficiently. Among 3-C precursors, glyceraldehyde gave maximum synthesis of folate activity. The cells appeared to utilize p-aminobenzoate preferentially to p-aminobenzoyl-glutamate. Pteroic acid appears to be an intermediate in the synthesis of folate derivatives in this system. Ascorbic acid stimulates the synthesis to a great extent.     

Effect of various analogues of D-glutamic acid on the D-glutamate-adding enzyme from Escherichis coli

Abstract Twenty-four analogues of D-glutamic acid were tested as substrates or inhibitors of the D-glutamate-adding enzyme from Escherichia coli . The best substrates were, in decreasing order of specific activity, D- erythro -4-methylglutamic acid, D- erythro - methylglutamic acid, DL-homocysteic acid, (±)- trans -1-amino-3-carboxy-cyclopentanecarboxylic acid and (±)- trans -1-amino-3-carboxy-cyclohexanecarboxylic acid. Among the different stereoisomers, only the D- erythro isomers for methylglutamic acids, and the trans isomers for the cyclic analogs, were substrates. Apart from the D- erythro -3 and 4-methylglutamic acids and DL-homocysteic acid, none of the examined compounds significantly inhibited the addition of radioactive D-glutamic acid to UDP-N-acetylmuramyl-L-alanine.     

Rapid solubility determination of the triterpenes oleanolic acid and ursolic acid by UV-spectroscopy in different solvents

Salvia triloba (Greek sage) has been used for the treatment of various diseases and contains two bioactive triterpene acids of major interest: oleanolic acid (OA) and ursolic acid (UA). The determination of the solubility of OA and UA in different solvents is a prerequisite to select the optimal solvent. The main goal of this work was to develop a quick method of predicting the solubility of OA/UA in different solvents to get a first indication of which solvents could be considered suitable for extraction from any plant material containing at least one of these triterpenes. A novel and simple ultra-violet spectroscopy method was developed for this purpose.The best solubilities were determined in THF, dioxane and n-butanol as well as in blends of dioxane and n-butanol.     

水杨酸对冷藏板栗贮藏效果的影响

以不同浓度水杨酸、不同浸果时间研究水杨酸对板栗果实冷藏效果的影响。结果表明:水杨酸可抑制贮藏期间栗果呼吸强度,推迟呼吸跃变的到来;还可抑制VC含量和淀粉含量;水杨酸处理后栗果腐烂率和质量损失率均降低。最佳处理方式为0.5 g/L水杨酸浸果10 m in。     

Gluconic acid production byPenicillium puberulum

Twenty-five Penicillium species isolated from Egyptian soil were examined for their ability to produce gluconic acid in surface culture. Of the eight species capable of producing gluconic acid, Penicillium puberulum gave the maximum yield (91% gluconic acid from glucose after 7 days of fermentation with 3% CaCO3). Peptone was the best nitrogen source for acid fermentation and glucose was superior to sucrose. Addition of low concentrations of KH2PO4 and MgSO4 - 7 H2O stimulated acid production. An initial pH of 6.1 was most favourable for acid accumulation and addition of CaCO3 was necessary for maximum acid production.     

Flux balance analysis in the production of clavulanic acid by Streptomyces clavuligerus

In this work, in silico flux balance analysis is used for predicting the metabolic behavior of Streptomyces clavuligerus during clavulanic acid production. To choose the best objective function for use in the analysis, three different optimization problems are evaluated inside the flux balance analysis formulation: (i) maximization of the specific growth rate, (ii) maximization of the ATP yield, and (iii) maximization of clavulanic acid production. Maximization of ATP yield showed the best predictions for the cellular behavior. Therefore, flux balance analysis using ATP as objective function was used for analyzing different scenarios of nutrient limitations toward establishing the effect of limiting the carbon, nitrogen, phosphorous, and oxygen sources on the growth and clavulanic acid production rates. Obtained results showed that ammonia and phosphate limitations are the ones most strongly affecting clavulanic acid biosynthesis. Furthermore, it was possible to identify the ornithine flux from the urea cycle and the α‐ketoglutarate flux from the TCA cycle as the most determinant internal fluxes for promoting clavulanic acid production. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1226–1236, 2015     

Biomarkers of myeloperoxidase-derived hypochlorous acid

Hypochlorous acid is the major strong oxidant generated by neutrophils. The heme enzyme myeloperoxidase catalyzes the production of hypochlorous acid from hydrogen peroxide and chloride. Although myeloperoxidase has been implicated in the tissue damage that occurs in numerous diseases that involve inflammatory cells, it has proven difficult to categorically demonstrate that it plays a crucial role in any pathology. This situation should soon be rectified with the advent of sensitive biomarkers for hypochlorous acid. In this review, we outline the advantages and limitations of chlorinated tyrosines, chlorohydrins, 5-chlorocytosine, protein carbonyls, antibodies that recognize HOCl-treated proteins, and glutathione sulfonamide as potential biomarkers of hypochlorous acid. Levels of 3-chlorotyrosine and 3,5-dichlorotyrosine are increased in proteins after exposure to low concentrations of hypochlorous acid and we conclude that their analysis by gas chromatography and mass spectrometry is currently the best method available for probing the involvement of oxidation by myeloperoxidase in the pathology of particular diseases. The appropriate use of other biomarkers should provide complementary information.Keywords-Free radicals, Myeloperoxidase, Neutrophil oxidant, Hypochlorous acid, Chlorotyrosine, Chlorohydrin, Oxidant biomarker     

Evaluation of gas chromatograph packings for the separation of butyric acid from serum-catalyzed hydrolysis of ethyl butyrate

Twelve synthetic and pilot adsorbents of different polarity and varying chemical composition were tested for the separation and quantitative determination of butyric acid from serum-catalyzed hydrolysis of ethyl butyrate. A gas chromatographic procedure with flame ionization detector (fld) using these adsorbents is satisfactory for the separation of butyric acid. The best results were obtained with Spheron SDA, Spheron BD, and Porapak R.     

Metabolism of arachidonic acid to eicosanoids within the nucleus

The eicosanoids are a diverse family of molecules that have powerful effects on cell function. They are best known as intercellular messengers, having autocrine and paracrine effects following their secretion from the cells that synthesize them. Many of the eicosanoids are produced from one polyunsaturated fatty acid, arachidonic acid. The diversity of possible products that can be synthesized from arachidonic acid is due, in part to the variety of enzymes that can act on it. Over the past 15 years, studies have placed many, but not all, of these enzymes at or inside the nucleus. In some cases, the nuclear import or export of arachidonic acid-processing enzymes is highly regulated. Furthermore, nuclear receptors that are activated by specific eicosanoids are known to exist. Taken together, these findings indicate that the enzymatic conversion of arachidonic acid to specific signaling molecules can occur in the nucleus, that it is regulated, and that the synthesized products may act within the nucleus. The objectives of this commentary are to review what is known about the metabolism of arachidonic acid to eicosanoids within the nucleus and to point to important areas for future discovery.     

Filtration assay for arachidonic acid release

Arachidonic acid (AA) release is a central message in cell signaling. Fatty acid release is generally assessed by manual sampling of radioactivity release from cells prelabeled with a radiolabeled fatty acid. The assay is laborious, time-consuming, and susceptible to high noise. Here we present a fast and reproducible method for 96-well filter plates and cells in suspension, a method that is best suited for agonist concentration-response studies and, thus, for ligand screening. The method offers tremendous time and effort savings and enables execution of large experimental series previously unattainable for AA release studies.     

A search for raw materials for the isolation of shikimic acid

The content of shikimic acid in the vegetative parts of a number of plants growing in the Altai Territory has been studied. The greatest content of shikimic acid (about 1.5%) was found in the coniferous needles of Scots pine. Shikimic acid accumulated in buckwheat cells cultivated in vitro on glyphosate-containing medium. The best results were obtained with buckwheat explants cultivated in vitro on Murashige and Skoog nutrient medium in the presence of 0.5 × 10^?3 mg/L of glyphosate.     

Separation of chlorogenic acid from honeysuckle crude extracts by macroporous resins

Chlorogenic acid, one of the most bioactive compounds rich in the Chinese medicinal herb honeysuckle, is a natural antioxidant and serves as anti-inflammatory, anti-tumor, anti-mutagenic and anti-carcinogenic agent. An efficient preparative separation process of chlorogenic acid from honeysuckle crude extracts has been developed in the present study. HPD-850 resin offers the best adsorption capacity, and adsorption and desorption ratios for chlorogenic acid among the nine macroporous resins tested, and its adsorption rate at 25 degrees C fit best to the Langmuir isotherm. The adsorption capacity of HPD-850 resin was found to depend strongly on the pH value of the initial adsorption solution. The dynamic adsorption and desorption experiments have been carried out on a HPD-850 resin packed column to optimize the separation process of chlorogenic acid from honeysuckle crude extracts. After one run treatment with HPD-850 resin, the chlorogenic acid content in the final product was increased 4.46-fold from 11.2% to 50.0%, with a recovery yield of 87.9%. The preparative separation of chlorogenic acid can be easily and efficiently achieved via adsorption and desorption on HPD-850 resin, and the method developed will provide a potential approach for large-scale separation and purification of chlorogenic acid for its wide pharmaceutical use.     

Alteration of the specificity of the cofactor-binding pocket of Corynebacterium 2,5-diketo-D-gluconic acid reductase A

The NADPH-dependent 2,5-diketo-D-gluconic acid (2,5-DKG) reductase enzyme is a required component in some novel biosynthetic vitamin C production processes. This enzyme catalyzes the conversion of 2,5-DKG to 2-keto-L-gulonic acid, which is an immediate precursor to L-ascorbic acid. Forty unique site-directed mutations were made at five residues in the cofactor-binding pocket of 2,5-DKG reductase A in an attempt to improve its ability to use NADH as a cofactor. NADH is more stable, less expensive and more prevalent in the cell than is NADPH. To the best of our knowledge, this is the first focused attempt to alter the cofactor specificity of a member of the aldo-keto reductase superfamily by engineering improved activity with NADH into the enzyme. Activity of the mutants with NADH or NADPH was assayed using activity-stained native polyacrylamide gels. Eight of the mutants at three different sites were identified as having improved activity with NADH. These mutants were purified and subjected to a kinetic characterization with NADH as a cofactor. The best mutant obtained, R238H, produced an almost 7-fold improvement in catalysis with NADH compared with the wild-type enzyme. Surprisingly, most of this catalytic improvement appeared to be due to an improvement in the apparent kcat for the reaction rather than a large improvement in the affinity of the enzyme for NADH.     

First total synthesis of (5Z,9Z)-(+/-)-2-methoxy-5,9-octadecadienoic acid, a marine derived methoxylated analog of taxoleic acid

The first total synthesis for the sponge derived (5Z,9Z)-(+/-)-2-methoxy-5,9-octadecadienoic acid, an analog of taxoleic acid, was accomplished in seven steps and in a 10% overall yield. It was again corroborated that the best strategy to prepare these cis,cis dimethylene interrupted double bonds is the double-alkyne bromide coupling reaction of 1,5-hexadiyne, which provides the advantage of achieving a 100% cis stereochemical purity for both double bonds after hydrogenation under Lindlar conditions. The alpha-methoxy functionality was best prepared via the Mukaiyama reaction of (4Z,8Z)-heptadecadienal with trimethylsilyl cyanide and triethylamine followed by acid hydrolysis. Selective methylation of the hydroxyl group of (5Z,9Z)-(+/-)-2-hydroxy-5,9-octadecadienoic acid was achieved with sodium hydride/methyl iodide when tetrahydrofuran was used as solvent. Complete spectral data is presented, for the first time, for this unusual marine alpha-methoxylated fatty acid.     

Comparative Effects of lndole-3-acetic acid, Abscisic acid, Gibberellic acid and 6-Benzylaminopurine on the Dark- and Light-induced Pulvinar Movements in Cassia fasciculata Michx

Effects of plant hormones were examined on the dark- and light-inducedmovements of Cassia fasciculata. Indole-3-acetic acid (IAA),gibberellic acid (GA₃) and 6-benzylaminopurine (6-BAP) inhibitedthe scotonastic movement whereas abscisic acid (ABA) enhancedit. After brief treatments (5 to 30 min), the ABA effect wasinhibitory rather than promotional. Hormonal treatment in theacidic range gave the best physiological response for ABA, butthe greatest efficiency of IAA, GA₃ and 6-BAP was obtained withpH values close to neutrality. Three to 5 h were needed beforeexpression of the physiological effect triggered by GA₃ and6-BAP, while 5 min treatments were sufficient for IAA and ABA.Light-induced movements were largely enhanced by IAA and slightlyby GA₃ but inhibited by 6-BAP and ABA. The results are discussedin relation to the ionic changes in the pulvinar motor cells,regulating leaflet movements. Key words: Abscisic acid, auxins, cytokinins, gibberellic acid, pulvinar movements